Explosive.



. for blasting lafid Blaclchejath, in the or BLACKHEATH, ENGLAND.

EXPLOSIVE.

Specification of Letters Patent.

ratenteo. April 9, 1907.

Application filed September 27, 1906. Serial No. 336,459.

Tea/ll wh'omtt may concern: 1

Be it known that I, OSWALD SILBERRAI), a ubject of the King of Great Britain and he and residing at 5]. Shooters Hill road, county of Kent, England, have invented certain new and useful Iin .prover'nents in Explosives, of which the folowing is a specification.

y invention relates to nitrogl cerin eX .PlOSIVGS, and is especially appliea )le to disi'uptive explosives for blasting purposes. arious explosives of-this class have been heretofore m anufactured in which Wood-pulp or the like-and an oxidizing, agent, such as so dium nitrate, have been mixed with a jelly formed by dissolving nitrocellulose in nitroglycerin. These explosives have, certain disadvantages, the chief of which are exudation, liability to deteriorate through l'iydrolytic decomposition, lack of plasticity, a tendency to freeze, and a tendency to crumble. i

The object of this invention is to produce a series of nitroglycerin explosives ha in; any desired power and velocityof detonation, according to the varying grades of rock or other material on which they are to be applied, the explosives, being at the same time free from the disadvantages above referred to and cheaper to manuiacturo than any cxplosives of the same power hitherto produced. In selecting the most eil'cctivecomposition rocks ol any particular degree of toughness it is necessary looity of detonation as well as the gas volume evolved on combustion. in preparing the explosive it is also necessary to consider the properties of the explosive asrcgards size of detonator necessary to give eil'cctivc ox plosion. 'The phy. al properties of the linishcd explosive and its form and keeping qualities are also of importance, the bcs t term for blasting purposes being that of a plastic mass. At the same time it is found that substances added to give the desired qualities in some respects interfere with other desirable ualities of the explosive; For instance, in deciding the ratio of soluble nitrocellulose to nitroglycerin a balance must be drawn between. diliiculty of detonation, on'thc one hand, and liability to exude, on the other. It is therefore essential in order to pri'iducc the-best result to consider the sheet on the explosive properties of the composition oi iugredients added for the purpose of improving to consider the ve-' howe ver,

' tune detonation and of or preserving the physical properties and generally to onsider the ell'cct of each. addition as regards every property it gives to the explosive. The cheapest source o'l power for explosives is a n'iixturo of Wood-'n'ical, pitch, resin, or sulfur with a suitable oxidizing agent, the cheapest of which at the present is sodium nitrate. Such mixtures are, however, far too weak for practical use, noccssitating the addition of a high explosive. The cheapest high explosive for the purpose is nitroglycerin, which is most conveniently added in thc'iorm of a jelly produced by dissolving soluble nitrocellulose in nitroglycerin. I find that the best practical results are obtained by the addition of such a jelly containing about four per cent'of soluble nitrocellulose to dopcs oi" wood-ineal,pitch, sul'lur, or resin and sodium nitrate or other oxidizing, agent,

My experiments show that a product of the most suitable consistency is obtained by mixing the nitroglycerin jolly with a dope (ontainin 'wooihmcalthirtypcrccut.and sodium nitrate seventy pcr cont/in the proportion ol' about lil'tv-two partsjclly to forty-eight parts i also liud that the same consistency is obtained with dupes containing a bituminous substance, such as pitch or rosin, to'clvo per cent. and sodium nitrate eighty-eight percent. in the proportion of about thirty-four parts jolly to sixty-six parts dope. it will be seen, therefore, that by the use of suitable proportions of the wood-meal dope and bituminous dopc i am enabled to vary the proportion of nitroglycerin jelly, and thus vary the power of the explosive, Without altering: its consistency, and accord this diil'crcncc in the absorptive properties of the dopcs-in order to produce explosives of dill'ercnt powers and velocities ol detonation suitable for various grades ol' rock and yet in all cases of poi-[hot plasticity.

My invention consists in the production ol an explosive of given power and velocity of the most suitable consistency by adding to a jolly ol' nitroglycerin and soluble nitrocellulose suitable proportions of wood-meal or rosin orpitch dopcs.

My invention lurthcr C-(JllSlSbSlll the production ol explosives containing the mixturcs (I, b, c. and a, described below, in approximately the following proportions:

Mixture u: l v .58.;3 parts Mixture I. 6,7'1uinus 1') par-ts} l per cent. Mixtuiuc. ,(ytimrs 2:) parts Mixture d e l l l 5 pct cont.

ed. For instance, for

Mixture a consists of-' 55.84 par-ts.

Nitro lycerin Soluh e nitrocellulose. 3. 52 parts. Naphthalene .82 part} or pitch Resin .82 part 1.64 parts. An oxidizing agent the al of oxygen 3. 4 parts oxygen. Mixture 7) consists of- An oxidizing agent the equivalent of oxygen 25. 7 parts oxygen. Wood-meal 30 parts. Mixture 0 consists of? Resin or pitch i 13 parts. An oxidizing agent t/lu Lqu of oxy 33.3 parts oxygen. Mixture d consists'of Sulfur I 0 part Sodium benzoatrfl... ,1 part. Ammonium perchlorate 3.9 parts. In the mixtures a b a sodium nitrate would be commonly used, the proportions being nine parts in mixture a, seventy parts in mixture b, and eighty-eight parts in mixture 0.

In mixture d the ammonium perchlorate'may i be replaced by any suitable oxidizing agent, the proportion being determined by the oxygen available in the agent chosen. The particular oxidizing agent used will depend upon the purpose for which the explosive is intenduse under water, an insoluble oxidizing agent, such as manganese dioxid or,an oxid oflead, may be used.

The Vall -e of y is about slightly according to the absorptive properties of the particular wood-meal used, While the quantity as varies with the power and rate of combustion of the explosive required,

as hereinafter described.

In the explosives above described and in. similar explosives I find that .:.the resin or pitch, in combination with the other ingredients, has also the fect of forming an air tight joint between the explosive used and ts wrapper,minimizing the effect of moisture.

In carrying my invention into elfectfor example, in the production of an'explosive suitable for blasting the toughest rocks-I use mixtures as above described taking as less than ten. For rocks of medium tough ness :1: would. betaken equal to about fifteen, while for the softest rocks as equals about thirty-seven. -These examples Will sufficiently show. the nature of the effect pro: duccd asrcgards power and velocity of (letonation of the various compositions made according to my invention.

In preparing the explosive according to my invention tlienitroglycerin jelly is prepared by" standin"g the nitroglycerin in troughs u'ntilit, is heated to about 120 Fahrenheit, and the added, the mixture being continually stirred until. the-mass is thoroughly mixed. about two hours the jelly so formed. is kneaded until it assumes a uniform, consistency. The dopes band 0 are meanwhile sidered in determining the 2.5, but Wlll vary' nitrocellulose is then in any known form of incor )orat1ngma' chine. The proportion of the chosen according expl opes will be i to the work for which the osive is required, as mentioned above. I It will be understood that the mixture d is non-essential and may be omitted, if desired, or according to circumstances. The mixture d, if required, is incorporated at the same time and renders it possible to use the I explosive with small detonators. It will be I found that with this addition detonators containing about 0.5 grams of fulminate are suflicient to give excellent results with all grades of explosives according to my invention.

In the compositions given I have specified sodium nitrate as the oxidizing agent. I may, however, use potassium salts or the l chlorates, the latter being preferable where moisture is to be feared, or in cases where a very cool explosive. is required ammonium nitrate is most suitable.' Ammonium'perchlorate may ailso be used throughout, as the oxidizing agent ,and is only suitable where the most violent. detonation is required. The effect of chlorates is to somewhat increase the velocity of detonation, and this must'be convalue of a: in-the above equation. I The deli uescent properties of explosives containing ygroscopic oxidizing agents are remedied to a great extent by the physical properties of the mixture, Whichby reason of 'the resin and napthalene or of the jelly makes an air-tig t joint with the containing wrapper in which the explosives are most conveniently made up. Exudation is rendered harmless by the presence of the naphthalena whichis capable of dissolv ing in nitroglycerin. The naphthalene tends of the explosive, where it readily combines with any traces of nitroglycerin which may exude. hydrocarbon capable of dissolving in nitroglycerin may be substi-tuted for this purpose.

he quantity of such hydrocarbons, should,

owever, not exceed about 0.5 per cent. in the. explosives designed for any particular power and velocity are present in greater proportions an alteration will in time be produced in the compost j'tion of the explosive. If. the proportion is I kept below 0.5,per cent, the loss from; this very dilute and highly viscid solution is so slow that no measurable alteration occurs in the-course of many years.

Apart from the effect tunnnous dope on the ve the-presence of resin or pitch is desirable in I order to retard hydrolytic dccom osition and to protect .the explosive from t e efi'ects of air and moisture. For this purpose the propitch m'presen'ce Phenanthrene or like sub-limable of detonation, as if they 1 produced by the bi-- ocity of detonation to sub-lime, and so concentrate-on the surface ITO 8 portion of resin or itch should not be less thirty-three parts of oxygen substantial? as an 0.8 per cent-o the nitroglycerinnitro 'r. escrib d andi the proportions specifie cellulose jelly. The presence of naphthaosive -comprisinglene either added as sue or present in the fi -eight parts of a mi h, is also beneficial, in t ii 'reezing-point of th found that sodium tion of about 0.1 per cent. has a bene cial effecton the keeping m sive,

my invention, what re to secure by Let- I 1 J t to t. 'rty-- ree parts of'oxygem'substantially as and roglycerin, fro hree to four p rts of solu for the purpose described; e nitrocellulose, 1 .6 parts of pitch and an n testimony WhereofI 'afiix my signature 40 0x1 izing agent equivalent to rom three to in presence of two Witnesses; our parts of oxygen, :1 mixture containin 2o thirty parts of wood-meal 11d an oxidizin ag'ent equivalent to t OSWALD SILBERRAD; wenty-five parts of oxy- Witnesses: gen; a mixture containing two ve parts of pitch, and an oxid"' WM. W. ADAMS, 'lZlDg agent equivalent to BnRrRAM, H. MAT'rHEws. 

